The present invention relates to adjustable clamps for securely fastening one object to another and more particularly to clamps for securely fastening a flexible hose about a pipe, a nipple, or the like, by means of an adjustable band which is adapted to be adjusted and closed by a pair of interlocking jaws. Specifically, the present invention relates to an improved snap-on clamp of the above type which is capable of withstanding high internal hose pressure, is adjustable to fit hoses having widely varying outer diameters for a given inner diameter hose size, and will conform and evenly apply pressure to the object being clamped.
In the construction and manufacture of apparatus which include gases or liquids flowing through partially flexible lines, installation of hose pieces between pipe connections is often necessary. In many cases, it is desirable to simply and quickly clamp the hose onto a nipple at the end of a pipeline. For purposes of servicing, repairing, or cleaning of such lines, it is also desirable to be able to disconnect the normally clamped-on hose without damaging either the hose or the clamp. Therefore, a removable clamp of simple construction and operation is necessary for such purpose.
It is another desirable feature in many instances to be able to re-use such clamps. In the automobile industry, for example, short flexible hose pieces are inserted into pipe connections which conduct air and liquids. It is also customary in the automotive industry to cover drive shafts by means of flexible, bellows-like hose pieces in order to protect the shafts against the environment. These hose pieces must generally be disconnected for purposes of repairs and/or servicing, and the ability to re-use the hose clamps would result in substantial cost savings. Conversely, it may also be desirable to clamp a hose onto a pipe or nipple in such a fashion that to disconnect the clamped hose could only be accomplished by destroying the clamp.
Heretofore, clamps for fastening a flexible hose onto a pipe, a nipple, or the like, have either been difficult and inconvenient to clamp, have not been adapted to securely clamp and hold the hose under conditions of high internal hose pressure, have not been readily removable, or have not been sufficiently adjustable for clamping hoses having virtually identical inner diameters but widely varying outer diameters.
Some examples of previous snap-on adjustable hose clamps are particular described in U.S. Pat. No. 3,605,200 and No. 3,925,851. The clamps disclosed in these two patents include open annular bands having interlocking jaw members at the ends of each band. While these prior clamps are adjustable and readily fastened about a flexible hose, they are limited with respect to the range of outer hose diameters which a single clamp is capable of being secured about. It has been recognized, in accordance with the present invention, however, that the limitations of such prior art clamps is due in part, to the tooth structure of the disclosed clamps, particularly with respect to the size and number of teeth in relation to the annular band configuration.
Such a limitation, of course, poses considerable problems since the manufacture of hoses is generally based on inner diameter sizing. Since such hoses fit over standard size nipples or pipe ends, the inner diameters of the hoses are generally maintained in accordance with strict size tolerances. The thicknesses and outer diameters of such hoses, however, generally do not have strict size tolerances and, therefore, vary widely for any given inner diameter size, even by as much as 0.09 inch and more. Furthermore, some high pressure hoses are necessarily quite thick and, therefore, have a large outer diameter in relation to their inner diameter. Thus, to meet all possible situations, users or installers of such hoses have been required in the past to stock perhaps as many as three different sizes of the prior snap-on hose clamps for any given inner diameter size of flexible hose. Obviously, such a procedure is costly. Furthermore, failure to maintain such a stock of prior art clamps has resulted in the inability at times to properly service certain situations where the available hose required a size of clamp which was out of stock or not stocked at all, even though other clamps suitable for the same inner diameter size hose were available.
Another problem with the aforementioned prior snap-on hose clamps has been the general inability to maintain the integrity of a hose connection under conditions of high internal hose pressures. It has also been recognized, in accordance with the present invention, that the configuration of the junction between the radially innermost tongue of one interlockable member and the jaw of the opposite interlockable member in such prior art hose clamps is such that the clamps tend to gather or pinch the hose material between the tongue and jaw as the clamps are tightened about a hose. In addition, pressure from the clamp is unevenly distributed about the hose thereby causing weak points in the clamped area. This has resulted at times in the inability of a clamped hose to withstand very high internal hose pressures in that the fluid carried within the hose has escaped through the gathered or pinched area. Thus, such prior snap-on hose clamps are inadequate in certain situations where high pressures, such as 200-300 psi or higher, are present within the clamped hose, and in some instances can fail at pressures as low as 15 psi.